更新文件XML [英] Update file XML

问题描述

我有一个问题:我有一个.xml文件.我想阅读并更新它.我写了代码:

I have a problem: I have a file .xml. I want read and update it. I written code:

private void Read_file()
        {
            XmlDocument document = new XmlDocument();
            document.Load(@"D:\\Help_file.xml");
            XmlNodeList myNoteList = document.GetElementsByTagName("product");
            foreach (XmlElement node in myNoteList)
            {
                if (node.GetAttribute("id") == "1005")
                {
                    richTextBox1.Text = node.SelectSingleNode("productName").InnerText;
                    //richTextBox2.Text = node.SelectSingleNode("productPrice").InnerText;
                }
                else if (node.GetAttribute("id") ==index)
                {
                    richTextBox2.Text = node.SelectSingleNode("productName").InnerText;
                }
            }
        }

和:

and :

private void Update_file()
        {
            FileStream fs = new FileStream(@"D:\\Help_file.xml", FileMode.Open);
            XmlTextWriter w = new XmlTextWriter(fs, Encoding.UTF8);
            XmlDocument document = new XmlDocument();
            //document.Load(@"D:\\Help_file.xml");
            XmlNodeList myNoteList = document.GetElementsByTagName("product");
            foreach (XmlElement node in myNoteList)
            {
                if (node.GetAttribute("id") == "1005")
                {
                    //richTextBox1.Text = node.SelectSingleNode("productName").InnerText;
                    w.WriteElementString("productName", richTextBox1.Text);
                    w.WriteEndElement();
                }
            }
        }

Read_file() 运行成功，但Update_file()不成功.
我不习惯使用xml.请帮助查看Update_file()功能.谢谢！

With Read_file() run successed but Update_file() do not successed.
I''m not used to using xml. Please help review Update_file() function. Thanks!

推荐答案

无论您使用XmlTextWriter做什么，即使您解决了问题，它也是错误的.您已经决定使用XmlDocument，请继续使用它！
从文件加载文件，将数据直接修改到文档节点上，并在准备好后写入此文档:

Whatever you do with XmlTextWriter, it''s wrong, even if you fix a problem. You already decided to use XmlDocument, keep using it!
Load it from file, modify data right onto document nodes, and write this document when ready:

public static void WriteXmlDocument(
        XmlDocument doc,
        outputFileName) {
    using (XmlTextWriter writer =
       new XmlTextWriter(outputFileName, Encoding.UTF8))) {
       writer.Formatting = Formatting.Indented;
       doc.WriteTo(writer);
   } //using (important to dispose writer, otherwise it may not flush)
} //WriteXmlDocument

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